I want to tell you about the health benefits of something called “urolithin A”—but I often lose people as soon as they hear “uro.”

So let’s get this out of the way first: Urolithin A isn’t a prescription drug for an enlarged prostate. It’s an all-natural compound your body produces when you eat certain foods.^1,2

And research shows it supports one of the fundamental mechanisms of aging: mitochondrial health.^2,3That’s essential for energy, brain function, and overall vitality.

Or put another way: The healthier your mitochondria, the younger you feel.

Plus, scientists have found that increasing urolithin A levels can increase strength… without strength training.⁴

If that grabbed you, good—because the next part is where it gets useful.

What Is Urolithin A?

Urolithin A is a substance produced by the bacteria in your gut after they break down plant chemicals found in foods like pomegranates, walnuts, and berries.

If you’re thinking, ‘I’m still not sure what urolithin A is,’ I don’t blame you. It’s hard to picture what’s going on—and why it matters—if you don’t have a bit more context.

So let’s back up for a moment, and I’ll quickly explain how it works in two (really brief) parts.

Part 1: It All Starts with Polyphenols

Plant foods are loaded with healthful chemicals known as polyphenols.

Most polyphenols pass through your stomach and small intestine largely unchanged. But once these polyphenols reach your colon, your gut microbes break them down into smaller compounds called metabolites.

Those metabolites are a big reason why polyphenol-rich foods are so good for you. Some enter your bloodstream and have body-wide benefits, such as:

helping lower inflammation
supporting brain and heart health
improving how your cells handle everyday stress

Part 2: From Pomegranates to Urolithin A

Pomegranates, walnuts, and berries are rich in polyphenols called ellagitannins.

When your gut bacteria breaks down these ellagitannins, one of the metabolites that’s created is… wait for it… urolithin A.

(In case you’re wondering, it’s usually pronounced “YOUR-oh-lith-in A.” That’s a mouthful but way easier to say than its full chemical name: “3,8-dihydroxy-6H-dibenzo[b,d]pyran-6-one.”)

What Does Urolithin A Do?

Urolithin A’s most compelling benefit is that it activates mitophagy—the process by which your body clears out old, dysfunctional mitochondria.

Mitochondria are tiny structures inside your cells that help convert the food you eat into usable energy. Every muscle contraction, every thought, every heartbeat depends on them.

Over time, mitochondria get worn down and damaged. When that happens, cells don’t produce as much energy—and they can contribute to ongoing, low-grade inflammation.

That combination is a hallmark of aging. It also makes you feel crap. Think: chronic fatigue, brain fog, and feeling less emotionally resilient.

Why mitophagy matters

Mitophagy is your cells’ way of preventing the slow buildup of damaged mitochondria.

Without it, worn-out mitochondria accumulate. Cells struggle to produce energy, and inflammatory activity rises.

Over time, that persistent, low-grade inflammation becomes part of what researchers call inflammaging—the chronic inflammatory state associated with aging.

By helping clear damaged mitochondria before they pile up, mitophagy helps reduce a key driver of that process.

That doesn’t stop you from getting older. But it may help slow one of the key mechanisms behind age-related fatigue, muscle decline, and inflammatory stress. In other words, many of the things that make you feel older.

Which sounds great, but there’s one problem…

Not Everyone Makes Urolithin A

Here’s something fascinating: Only about 30 to 40 percent of people seem to have the gut microbiome capable of converting ellagitannins into meaningful amounts of urolithin A.⁵

That means you can eat pomegranates regularly and still produce very little.

And if you don’t regularly eat pomegranates, walnuts, or berries? You’re not likely to produce much period. In one study of 100 healthy adults, only 12 percent even had detectable urolithin A levels.⁵

Enter supplementation.

In that same study, a 500 mg urolithin A supplement led to six times higher blood levels over the next day than pomegranate juice—and the results were consistent across people.⁵

So with supplementation, most people can reliably raise their levels.

Now the real question becomes: What happens when you do?

The Science of Urolithin A

In laboratory studies, giving urolithin A to worms extended their lifespan and improved markers of mitochondrial function.⁶

Worms aren’t humans.

But mitochondrial biology is remarkably similar across species. The same cellular cleanup process—mitophagy—exists in worms, mice, and people.

So the next big step was to test it in humans. And that’s where things get more practical.

What Happens in People?

In humans, researchers can’t measure lifespan.

So they measure strength, endurance, and biomarkers linked to aging biology. There are a couple of really interesting studies so far.

Study #1

In a four-month clinical trial of overweight, middle-aged adults with low fitness levels, participants took either 500 mg or 1,000 mg of urolithin A daily—and made no major changes to their diet or physical activity.⁴

The results: Compared to placebo, both urolithin A groups significantly improved lower-body strength—by about 10 percent.

By contrast, the placebo group lost about 10 percent of hamstring strength over the same period.

The 1,000 mg group also increased their aerobic fitness by 10 percent.

So without adding an exercise program, the people who took 1,000 mg of urolithin A improved both strength and fitness.

Study #2

In a 2025 randomized, placebo-controlled trial published in Nature Aging, 50 healthy middle-aged adults took 1,000 mg of urolithin A daily for four weeks.⁷

Compared to the placebo group, those taking urolithin A had significantly lower levels of C-reactive protein (CRP), a widely used marker of systemic inflammation. Researchers also observed measurable changes inside immune cells consistent with improved mitochondrial function.

We’re Still Figuring This Out

Not every study shows a clear advantage over placebo on every performance measure.

For example, in a four-month trial in adults ages 65 to 90, the urolithin A group increased their six-minute walk distance—a measure of real-world mobility—by about 15 percent from baseline.⁸ Surprisingly, the placebo group improved too (about 10%). So the difference between groups wasn’t statistically significant.

Across studies, though, researchers keep seeing the same theme: significant improvements tied to mitochondrial function, along with lower inflammation markers like CRP.^2,3,4,7,8

It comes down to this: Urolithin A has real biological effects—but most people probably aren’t making much of it, either because they aren’t eating many of the right plant foods, or because their gut microbiome can’t convert those plant compounds into urolithin A.

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